1. Field of the Invention
This invention relates to a novel phosphorescent keyhole locator in combination with a tumbler-like lock and to the keyhole locator itself.
2. The Description of the Prior Art
A common problem in modern society is to locate the keyhole of a lock in both lighted places and, especially, in dark places. The lock may be in the door of an automobile, in the door of a building, in a door handle, in a filing cabinet, etc. A tumbler-type lock, which may be of the lever-type, disc-type, or pin-type, is the most common type of lock used today. These locks include a tumbler portion having an external circular tumbler end surface which has a keyhole therein. This lock also includes a peripheral portion having an external peripheral end surface around the tumbler end surface.
A keyhole is quite small and the proper key for the keyhole must be properly oriented with respect to the keyhole to slide the key into the keyhole. To assist in finding the keyhole and to properly insert the key therein, various illuminators have been suggested previously. For example, U.S. Pat. No. 4,234,909 to P. R. Cotroneo describes an illuminator for the door lock of an automobile including an electric lamp, wires to a power source, a switch and a plastic plate to distribute light from the lamp to the keyhole. U.S. Pat. No. 3,719,821 to L. Foreman describes an illuminator attachment for a door knob comprising a lamp, a switch, a battery, wires connecting the lamp to the battery and a light port to guide light from the lamp to a keyhole in the door knob. These patents, and patents cited therein, all describe devices which need a source of electric power, a switch, wiring, and other structures. In addition, these prior devices require maintenance after they have been installed.
The prior art also describes phosphorescent materials; that is, materials which emit visible light for many hours after they have been exposed to visible light. These materials are to be distinguished from other luminescent materials which need to be excited with ultraviolet light, or cathode rays, or the like, and continue to emit for only a short time after excitation has stopped, usually for minutes or fractions of a minute. Devices employing phosphorescent materials are described in U.S. Pat. No. 3,978,340 to B.J. Schroeder for a backing sheet; U.S. Pat. No. 4,242,831 to J.F. O'Shaughnessy for a toy; U.S. Pat. No. 4,360,557 to J. A. Miller for a stair tread; U.S. Pat. No. 4,401,050 to L.D. Britt et. al. for a sign; and U.S. Pat. No. 4,629,583 to P.J. Gognan for shoe parts. None of these prior uses of phosphorescent materials is adapted to aid in locating the keyhole of a lock.